-from itertools import chain
-from subprocess import CalledProcessError, PIPE, Popen
-from sys import argv
-
-###
-
-import compiler
-
-class Unsafe_Source_Error(Exception):
- def __init__(self,error,descr = None,node = None):
- self.error = error
- self.descr = descr
- self.node = node
- self.lineno = getattr(node,"lineno",None)
-
- def __repr__(self):
- return "Line %d. %s: %s" % (self.lineno, self.error, self.descr)
- __str__ = __repr__
-
-class SafeEval(object):
-
- def visit(self, node,**kw):
- cls = node.__class__
- meth = getattr(self,'visit'+cls.__name__,self.default)
- return meth(node, **kw)
-
- def default(self, node, **kw):
- for child in node.getChildNodes():
- return self.visit(child, **kw)
-
- visitExpression = default
-
- def visitConst(self, node, **kw):
- return node.value
-
- def visitDict(self,node,**kw):
- return dict([(self.visit(k),self.visit(v)) for k,v in node.items])
-
- def visitTuple(self,node, **kw):
- return tuple(self.visit(i) for i in node.nodes)
-
- def visitList(self,node, **kw):
- return [self.visit(i) for i in node.nodes]
-
-class SafeEvalWithErrors(SafeEval):
-
- def default(self, node, **kw):
- raise Unsafe_Source_Error("Unsupported source construct",
- node.__class__,node)
-
- def visitName(self,node, **kw):
- if node.name == 'None': return None
- raise Unsafe_Source_Error("Strings must be quoted",
- node.name, node)
-
- # Add more specific errors if desired
-
-def safe_eval(source, fail_on_error = True):
- if source.strip() == '': return None
- walker = fail_on_error and SafeEvalWithErrors() or SafeEval()
- try:
- ast = compiler.parse(source,"eval")
- except SyntaxError, err:
- raise
- try:
- return walker.visit(ast)
- except Unsafe_Source_Error, err:
- raise
-
-###
-
-def run(cmd):
- """
- Run the given command (a list of program and argument strings) and return the
- stdout as a string, raising a CalledProcessError if the program exited with a
- non-zero status.
- """
- p = Popen(cmd, stdout=PIPE)
- stdout = p.communicate()[0]
- if p.returncode != 0: raise CalledProcessError(p.returncode, cmd)
- return stdout